Mounting structure of variable valve for dual exhaust system

ABSTRACT

A mounting structure of a variable valve for a dual exhaust system may include a muffler, at a front end of which is connected a first inlet pipe, and at a rear end of which is connected a first outlet pipe, and a Helmholtz Resonator, at the front end of which is connected a second inlet pipe, and at a rear end of which is connected a second outlet pipe, in which a variable valve which is opened and closed by an Electronic Control Unit (ECU) of a car is disposed on the second outlet pipe connected to the Helmholtz Resonator.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to Korean Patent Application No.10-2015-0037918 filed Mar. 19, 2015, the entire contents of which isincorporated herein for all purposes by this reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a mounting structure of variable valvefor dual exhaust system. More particularly, the present inventionrelates to a mounting structure of variable valve for dual exhaustsystem in which a Helmholtz Resonator is formed to be relatively smallcompared to a muffler and a variable valve is mounted at the rear end ofthe Helmholtz Resonator so that a second outlet pipe is selectivelyopened and closed, whereby the reduction of the booming noise and themaximization of the power performance can be achieved at the same timeand the production cost can be significantly reduced.

2. Description of Related Art

The noise entered into the inside of the car is caused by a variety offactors such as engine driving, road surface bending, or wind flowedinto the car during travel, and a variety of devices are used to reducethe noise.

In particular, since the exhaust gas combusted in the inside of theengine of the car is considerably high temperature and the velocitythereof almost amounts to the speed of sound so that if it is dischargedinto the atmosphere as it is, then it is abruptly expanded and producesthe violent sound, a separate muffler is mounted on the exhaust gas pathof the car to lower the temperature and the pressure of the exhaust gasso as to reduce the exhaust sound.

In general, a muffler is formed in the form of barrel of a predeterminedsize, and inside thereof are mounted a plurality of pipes and baffles sothat the exhaust sound can be lowered by inducing the expansion,resonance and the sound absorption of the exhaust gas at a time of flowof the exhaust gas.

Meanwhile, this muffler has a problem in that if the exhaust gasresistance is raised to reduce the exhaust sound, the resistance appliedto the exhaust gas stroke, that is, the back pressure is raised so thatthe output of the engine is lowered, and to the contrary, if the exhaustgas resistance is lowered to prevent the output loss of the engine, theexhaust sound is increased.

To solve such a problem, a muffler installed with a variable valve isdeveloped and used to raise the back pressure in the low speed intervalin which the exhaust sound becomes a problem and to lower the backpressure in the middle and high speed intervals in which the engineoutput becomes a problem.

FIG. 1 is a top view showing a conventional mounting structure ofvariable valve for dual exhaust system.

As shown in FIG. 1, the conventional dual exhaust system comprises afirst inlet pipe 1 and a second inlet pipe 1′ which are branched intotwo pipes so that the exhaust gas discharged from the engine of the carcan be flowed, a first muffler 2 and a second muffler 2′ reducing theexhaust sound by being respectively connected to the first inlet pipeand the second inlet pipe, and a first outlet pipe 3 and a first outletpipe 3′ each discharging the exhaust gas having passed the first mufflerand the second muffler to the outside of the car.

At this time, a first variable valve 4 and a second variable valve 4′which are controlled by the Electronic Control Unit (ECU) of the car arerespectively installed on the first outlet pipe 3 and the second outletpipe 3′ so as to differentiate the level of the exhaust sound and theback pressure according to the travel condition of the car.

However, the conventional mounting structure of variable valve for dualexhaust system has the problem in that, since the first variable valve 4and the second variable valve 4′ should be respectively installed onboth sides of the first outlet pipe 3 and the second outlet pipe 3′,there is a difficulty in the respect of production cost.

In addition, there are problems in that the conventional first variablevalve 4 and the second variable valve 4′ are respectively installed inthe space between the first muffler 2 and the first tail pipe 5 and inthe space between the second muffler 2′ and the second tail pipe 5′ sothat the composition of the package is difficult, and the entire size ofthe muffler 2, 2′ is reduced to prepare the installation space for thevariable valves 4, 4′.

The information disclosed in this Background of the Invention section isonly for enhancement of understanding of the general background of theinvention and should not be taken as an acknowledgement or any form ofsuggestion that this information forms the prior art already known to aperson skilled in the art.

BRIEF SUMMARY

Various aspects of the present invention are directed to providing amounting structure of variable valve for dual exhaust system in whichone variable valve is installed only at the rear end of the HelmholtzResonator unlike the prior art so that the production cost and the carweight are significantly reduced.

Furthermore, various aspects of the present invention are directed toproviding a mounting structure of variable valve for dual exhaust systemin which, although only one variable valve is installed, the boomingnoise is significantly reduced compared to the conventional car and thepower performance is maximized.

According to various aspects of the present invention, a mountingstructure of a variable valve for a dual exhaust system may include amuffler, at a front end of which is connected a first inlet pipe, and ata rear end of which is connected a first outlet pipe, and a HelmholtzResonator, at the front end of which is connected a second inlet pipe,and at a rear end of which is connected a second outlet pipe, in which avariable valve which is opened and closed by an Electronic Control Unit(ECU) of a car may be disposed on the second outlet pipe connected tothe Helmholtz Resonator.

The Helmholtz Resonator may be constructed to have relatively small sizethan the muffler so that the muffler and the Helmholtz Resonator arearranged asymmetrically.

The Helmholtz Resonator may include a housing, into an inside of whichexhaust gas flows and a rear end of which is opened, a first bafflearranged transversely in the housing, a second baffle combinedtransversely to close the rear end of the housing, and a resonantchamber partitioned by the first baffle and the second baffle.

At a time of low load travel of the car, the second outlet pipe may beclosed by the variable valve and the exhaust gas may flow in the secondinlet pipe and an inside of the Helmholtz Resonator so that a boomingnoise of the car is significantly reduced.

At a time of high load travel of the car, the second outlet pipe may beopened by the variable valve and the exhaust gas may be discharged to anoutside of the car through the first outlet pipe and the second outletpipe.

It is understood that the term “vehicle” or “vehicular” or other similarterms as used herein is inclusive of motor vehicles in general such aspassenger automobiles including sports utility vehicles (SUV), buses,trucks, various commercial vehicles, watercraft including a variety ofboats and ships, aircraft, and the like, and includes hybrid vehicles,electric vehicles, plug-in hybrid electric vehicles, hydrogen-poweredvehicles and other alternative fuel vehicles (e.g., fuel derived fromresources other than petroleum). As referred to herein, a hybrid vehicleis a vehicle that has two or more sources of power, for example, bothgasoline-powered and electric-powered vehicles.

The methods and apparatuses of the present invention have other featuresand advantages which will be apparent from or are set forth in moredetail in the accompanying drawings, which are incorporated herein, andthe following Detailed Description, which together serve to explaincertain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view showing a conventional mounting structure ofvariable valve for dual exhaust system according to the related art.

FIG. 2A and FIG. 2B are top views showing an entire configuration of anexemplary mounting structure of variable valve for dual exhaust systemaccording to the present invention.

FIG. 3 is a perspective view showing the configuration of the exemplaryvariable valve according to the present invention.

FIG. 4 is a projective top view showing a configuration of HelmholtzResonator according to the present invention.

FIG. 5 shows graphs comparing a result of analysis of transmission lossvarying upon opening/closing of the variable valve according to thepresent invention.

FIG. 6 shows graphs comparing a tail pipe noise varying uponopening/closing of the variable valve according to the presentinvention.

FIG. 7 shows graphs comparing an exhaust sound of the exemplary mountingstructure of variable valve for dual exhaust system according to thepresent invention and an exhaust sound of the conventional mountingstructure of variable valve for dual exhaust system at the time of slowacceleration of a car.

FIG. 8 shows graphs comparing an exhaust sound of the exemplary mountingstructure of variable valve for dual exhaust system according to an thepresent invention and an exhaust sound of the conventional mountingstructure of variable valve for dual exhaust system at the time of rapidacceleration of the car.

FIG. 9 shows graphs comparing pressure of the exemplary mountingstructure of variable valve for dual exhaust system according to thepresent invention and back pressure of the conventional mountingstructure of variable valve for dual exhaust system.

It should be understood that the appended drawings are not necessarilyto scale, presenting a somewhat simplified representation of variousfeatures illustrative of the basic principles of the invention. Thespecific design features of the present invention as disclosed herein,including, for example, specific dimensions, orientations, locations,and shapes will be determined in part by the particular intendedapplication and use environment.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments of thepresent invention(s), examples of which are illustrated in theaccompanying drawings and described below. While the invention(s) willbe described in conjunction with exemplary embodiments, it will beunderstood that the present description is not intended to limit theinvention(s) to those exemplary embodiments. On the contrary, theinvention(s) is/are intended to cover not only the exemplaryembodiments, but also various alternatives, modifications, equivalentsand other embodiments, which may be included within the spirit and scopeof the invention as defined by the appended claims.

FIG. 2A and FIG. 2B are top views showing the entire configuration ofthe mounting structure of variable valve for dual exhaust systemaccording to various embodiments of the present invention, FIG. 3 is aperspective view showing the configuration of the variable valveaccording to various embodiments of the present invention, and FIG. 4 isa projective top view showing the configuration of the HelmholtzResonator according to various embodiments of the present invention.

As shown in FIG. 2A and FIG. 2B, the exhaust gas discharged from anengine of the car flows into the muffler 10 and the Helmholtz Resonator20 through the first inlet pipe 11 and the second inlet pipe 21 branchedinto two pipes.

In various embodiments, the first inlet pipe 11 is arranged at the lefthand of the car and the second inlet pipe 21 is arranged at the righthand of the car, and in the likewise manner, the muffler 10 is arrangedat the left hand of the car and the Helmholtz Resonator 20 is arrangedat the right of the car, however, the reverse configuration is alsopossible.

The first outlet pipe 12 and the second outlet pipe 22 are connected tothe rear end of the muffler 10 and the Helmholtz Resonator 20respectively, and the first outlet pipe 12 and the second outlet pipe 22play role of discharging the exhaust gas, which passed the muffler 10and the Helmholtz Resonator 20, to the outside of the car.

The inside of the muffler 10 is partitioned by a number of baffleslikewise the typical muffler, and in the muffler 10 are arranged thefirst inlet pipe 11, the first outlet pipe 12 and the middle pipe 13 inconsideration of the flow of the exhaust gas.

On the second outlet pipe 22 connected to the Helmholtz Resonator 20 isinstalled a variable valve 30 which opens and closes the second outletpipe 22 by being controlled by an Electric Control Unit (ECU) of thecar.

At this time, unlike in the conventional structure of dual exhaustsystem the variable valves (4, 4′ of FIG. 1) are arranged at both outletpipes (3, 3′ of FIG. 1), in the structure of dual exhaust systemaccording to the present invention, the variable valve 30 is mountedonly at the second outlet pipe 22.

This is possible since, unlike the prior art, in the present invention,on both sides are not installed identical mufflers (2, 2′ of FIG. 1),but on one side is installed the muffler 10 and on the other side isinstalled the Helmholtz Resonator 20.

As shown in FIG. 3, the variable valve 30 comprises a rotational motor31 which is actuated by the ECU according to the travel condition (carspeed, load and the like) of the car, and a valve cover 32 of the formof the circular plate which is rotated according to the actuation of therotational motor.

Specifically, at the time of low load travel of the car (low speedtravel, low acceleration travel, downward slope travel and the like),the rotational motor 31 is actuated so that the valve cover 32 coincideswith the section of the second outlet pipe 22 so as to not allow theexhaust gas to pass.

On the contrary, at the time of high load travel of the car (high speedtravel, rapid acceleration travel, upward slope travel and the like),the rotational motor 31 is actuated so that the valve cover 32 isarranged perpendicular to the section of the second outlet pipe 22 so asto allow the exhaust gas to pass.

At this time, since the Helmholtz Resonator 20 is constructed to haverelatively small size than the muffler 10 so that the muffler 10 and theHelmholtz Resonator 20 are arranged asymmetrically, in the presentinvention, it is not necessary to reduce the size of the muffler 10 toinstall the variable valve 30.

Thinking in reverse, the muffler 10 according to the present inventionmay be formed to be further larger than the conventional muffler (2, 2′of FIG. 1), and accordingly the designer of the muffler 10 can designthe muffler 10 to realize the optimum noise characteristics withouthaving limitation of layout.

As shown in FIG. 4, the Helmholtz Resonator 20 comprises a housing 23into inside of which the exhaust gas flows and the rear end of which isopened, a first baffle 24 arranged transversely in the housing, a secondbaffle 25 combined transversely to close the rear end of the housing,and a resonant chamber 26 partitioned by the first baffle 24 and thesecond baffle 25.

The Helmholtz Resonator was devised by Helmholtz a German physiologistto separate a single sound from a complex sound and is widely used inmechanical system to reduce the flow noise in the duct.

In general, the resonator includes a cavity of significantly largevolume and a neck, and the narrow band noise is reduced by making theresonant frequency, which is determined by the geometrical informationof the cavity and the neck, consistent with the noise frequency of theduct.

In various embodiments, at the time of low load travel of the car, thesecond outlet pipe 22 is closed by the variable valve 30, the resonantchamber 26 plays the role of the cavity, and the second inlet pipe 21plays the role of the neck, so that accordingly the booming noise of theexhaust gas passing through the inside of the muffler 10 issignificantly reduced.

At the time of high load travel of the car, the second outlet pipe 22 isopened by the variable valve 30, and the exhaust gas is discharged tothe outside through the first outlet pipe 12 and the second outlet pipe22, whereby the power performance of the car is improved.

That is, the Helmholtz Resonator 20 according to the present inventionplays the role of low frequency resonator at the time of low load travelof the car, and plays the role of the muffler in which the flow path isexpanded and the back pressure is significantly reduced at the time oflow load travel of the car.

At this time, the second outlet pipe 22 is formed in the linear shapeunlike the outlet pipe used in the conventional typical muffler, so thatthe exhaust gas can be directly discharged, thereby having a significanteffect in reducing the back pressure at the time of high load travel.

FIG. 5 shows graphs comparing the result of analysis of transmissionloss varying upon opening/closing of the variable valve according tovarious embodiments of the present invention, and FIG. 6 shows graphscomparing the tail pipe noise varying upon opening/closing of thevariable valve according to various embodiments of the presentinvention.

In general, the capacity of noise reduction is represented by thetransmission loss curve obtained at the frequency zone, and to achievethe effective noise reduction, the peak frequency of the transmissionloss curve should be consistent with the noise frequency.

As shown in FIG. 5, when comparing the transmission loss curve at thetime of closing the variable valve 30 according to the present inventionwith the transmission loss curve at the time of opening the variablevalve 30, it can be seen that the transmission loss curve at the time ofclosing the variable valve 30 has peak value at the low frequency zone.

That is, it can be seen that if the variable valve 30 is closed, theHelmholtz Resonator 20 has the effective noise reduction characteristicsin the low frequency zone, and accordingly the booming noise of the caris reduced.

This is more obvious from the graphs comparing the tail pipe noise shownin FIG. 6. As shown in FIG. 6, it can be seen that the tail pipe noiseat the time of closing the variable valve 30 in the low Revolution PerMinute (RPM) stage is significantly reduced compared to the tail pipenoise at the time of opening the variable valve 30, and accordingly thestarting booming noise of the car is significantly reduced.

FIG. 7 shows graphs comparing the exhaust sound of the mountingstructure of variable valve for dual exhaust system according to variousembodiments of the present invention and the exhaust sound of theconventional mounting structure of variable valve for dual exhaustsystem at the time of slow acceleration of the car, FIG. 8 shows graphscomparing the exhaust sound of the mounting structure of variable valvefor dual exhaust system according to various embodiments of the presentinvention and the exhaust sound of the conventional mounting structureof variable valve for dual exhaust system at the time of rapidacceleration of the car, and FIG. 9 shows graphs comparing the backpressure of the mounting structure of variable valve for dual exhaustsystem according to various embodiments of the present invention and theback pressure of the conventional mounting structure of variable valvefor dual exhaust system.

Specifically, FIG. 7 shows the graphs comparing the exhaust sound in thecondition of Accelerator Position Sensor (APS) 30% when applying themounting structure of variable valve for dual exhaust system accordingto the present invention and the conventional mounting structure ofvariable valve for dual exhaust system to the real car.

As shown in FIG. 7, it can be seen that, at the time of slowacceleration of the car, the structure according to the presentinvention has the effect that the starting booming noise is reduced byabout 10% in the low RPM zone (about 2000 RPM or below) compared to theconventional structure, and the acceleration linearity (shown in dottedline in FIG. 7) is secured so that there is the effect in favor of therealization of the dynamic sound quality.

FIG. 8 shows the graphs comparing the exhaust sound in the condition ofWOP (Wide Open Throttle) when applying the mounting structure ofvariable valve for dual exhaust system according to the presentinvention and the conventional mounting structure of variable valve fordual exhaust system to the real car.

As shown in FIG. 8, at the time of rapid acceleration of the car, thestructure according to the present invention has the effect that thedynamic exhaust gas sound quality and the power performance aremaximized in the high RPM zone (about 2000 RPM or above) compared to theconventional structure.

Furthermore, as shown in FIG. 9, even when reviewing the back pressureaccording to the flow rate of the exhaust gas, the structure accordingto the present invention has the effect that the back pressure issignificantly reduced compared to the conventional structure.

Therefore, regardless of the fact that the present invention uses onevariable valve 30, the present invention has the improved effect in allrespect compared to the structure using two conventional variable valves(4, 4′ in FIG. 1) that the starting booming noise is reduced in the lowRPM zone and the power performance is improved in the high RPM zone.

The present invention having the structure described above has theeffect of reducing the production cost and the car weight by installingone variable valve only on the second outlet pipe 22 connected to therear end of the Helmholtz Resonator 20 compared to installing thevariable valves on both sides.

Furthermore, the present invention has the advantage in that since theHelmholtz Resonator 20 is formed to have relatively small size than themuffler 10 so that the muffler 10 and the Helmholtz Resonator 20 arearranged asymmetrically, it is not necessary to reduce the size of themuffler to install the variable valve.

In addition, the present invention has the effect that although thevariable valve 30 is installed only on the Helmholtz Resonator 20, thesecond inlet pipe 22 and the Helmholtz Resonator 20 play the role of lowfrequency resonator at the time of low load travel (at the time of slowacceleration) so that the booming noise is significantly reducedcompared to the prior art.

Furthermore, the present invention has the effect that the variablevalve installed on the Helmholtz Resonator is opened so that thesectional area of the outlet pipe is increased at the time of high loadtravel (at the time of rapid acceleration), whereby the powerperformance of the car and the dynamic exhaust sound quality aremaximized compared to the prior art.

As a conclusion, in the present invention, there occurs the effect thatthe production cost and the car weight are reduced compared to the priorart and at the same time the exhaust gas performance and the powerperformance are improved so that the marketability of the car isincreased.

The foregoing descriptions of specific exemplary embodiments of thepresent invention have been presented for purposes of illustration anddescription. They are not intended to be exhaustive or to limit theinvention to the precise forms disclosed, and obviously manymodifications and variations are possible in light of the aboveteachings. The exemplary embodiments were chosen and described in orderto explain certain principles of the invention and their practicalapplication, to thereby enable others skilled in the art to make andutilize various exemplary embodiments of the present invention, as wellas various alternatives and modifications thereof. It is intended thatthe scope of the invention be defined by the Claims appended hereto andtheir equivalents.

What is claimed is:
 1. A mounting structure of a variable valve for adual exhaust system comprising: a muffler, at a front end of which isconnected a first inlet pipe, and at a rear end of which is connected afirst outlet pipe; and a Helmholtz Resonator, at the front end of whichis connected a second inlet pipe, and at a rear end of which isconnected a second outlet pipe; wherein a variable valve which is openedand closed by an Electronic Control Unit (ECU) of a car is disposed onthe second outlet pipe connected to the Helmholtz Resonator.
 2. Themounting structure of the variable valve for the dual exhaust system ofclaim 1, wherein the Helmholtz Resonator is constructed to haverelatively small size than the muffler so that the muffler and theHelmholtz Resonator are arranged asymmetrically.
 3. The mountingstructure of the variable valve for the dual exhaust system of claim 1,wherein the Helmholtz Resonator comprises: a housing, into an inside ofwhich exhaust gas flows and a rear end of which is opened; a firstbaffle arranged transversely in the housing; a second baffle combinedtransversely to close the rear end of the housing; and a resonantchamber partitioned by the first baffle and the second baffle.
 4. Themounting structure of the variable valve for the dual exhaust system ofclaim 1, wherein, at a time of low load travel of the car, the secondoutlet pipe is closed by the variable valve and the exhaust gas flows inthe second inlet pipe and an inside of the Helmholtz Resonator so that abooming noise of the car is significantly reduced.
 5. The mountingstructure of the variable valve for the dual exhaust system of claim 1,wherein, at a time of high load travel of the car, the second outletpipe is opened by the variable valve and the exhaust gas is dischargedto an outside of the car through the first outlet pipe and the secondoutlet pipe.